Snow plow cylinder diagram? Cushion Valve?

[polemidis]

I realized that the bucket is not at all an efficient way to clear the snow from a driveway, so the last few days I designed a snowplow for my LS that I will angle the blade with the 3rd function (I purchased the WR Long kit)

I am trying to figure out 2 things
a) Cushion protection. Of course I will add the springs that can tilt the blade if I hit something. But if the blade is angled at 30deg when I hit something with the outer part of the blade , I am not sure that all the force will go to tilt, but tather than wanting to push back the blade. Will that cause too much pressure on the system that may damage the solenoid valve of the 3rd function? Or some other component? I was wondering if there is a way that after some point, the blade would just retract. I found a cushion valve. Is it what I am looking for, and does my thinking make sense?

b) 2 SA cylinders vs 2 DA cylinders or even 1 DA cylinder. The cost difference betwwen SA and DA is minor. I get it that a DA has a lot less force on retracting. But with a 2" bore cylinder the retract force will still be more than the force of a common 1.125 SA cylinder. Correct?
If I go with 2 DA cylinders, Should I connect the extend port of the 1st to the retract port of the 2nd one?
Anything else that I am missing?

Thank you guys!

 

[Rustyiron]

A "crossover" valve is popular with 2 s-a cylinders for us using an old truck plow, a very inexpensive build relatively speaking. Even new s-a "plow cylinders are pretty cheap if your building from scratch and the size of them & the mounting is much less cumbersome than even the smallest d-a cyl.

This valve is pictured above and basically if a preset pressure is reached on either cyl. (by striking an object) that pressure is directed to the other cyl. allowing it to retract (relieve the pressure) until it falls below that preset psi.

 

[George2615]

I use two SA standard truck plow cylinders and the same cushion valve. Left at the factory setting the valve does allow relief when one side of the blade hits something solid. I bought my cylinders used and rebuilt at a local truck plow installation place. They are much cheaper than buying the cylinders like in the OP's drawing.

 

[LD1]

Forget a da cylinder. No way to make a crossover work. And you are right about the potential to over pressurize the system. Unlikely you will damage a valve, but bending a rod....or boost likely blowing a hose.

Two days cylinders will work, and can still incorporate the crossover / cushion valve. As volumes will be equal. But twice the plumbing and really not necessary.

Standard plow cylinders are 1.5" not 1.125. so they are more powerful than you are giving them credit for.

Rear blades that incorporate an angle cylinder....compensate for this problem by using a much larger diameter cylinder. Which minimizes the pressure in the system if you strike an object. A lighter weight 7' blade uses 3" or bigger cylinders. Not the small 1.5" cylinders that are on a plow

 

[LD1]

Oh, and the plow cylinders.....1.5" x 10" stroke.....usually in the $70 range each. So quite affordable

 

[Ford850]

I use two SA standard truck plow cylinders and the same cushion valve. Left at the factory setting the valve does allow relief when one side of the blade hits something solid. I bought my cylinders used and rebuilt at a local truck plow installation place. They are much cheaper than buying the cylinders like in the OP's drawing.

This is the design to use too. A floating blade with a chain. :thumbsup:

 

[polemidis]

Thank you all for your quick answers! So SA cylinders and the cushion valve.

Rear blades that incorporate an angle cylinder....compensate for this problem by using a much larger diameter cylinder. Which minimizes the pressure in the system if you strike an object. A lighter weight 7' blade uses 3" or bigger cylinders. Not the small 1.5" cylinders that are on a plow

LD1 what about to go with bigger than 1.5, maybe 2" cylinders? I do not care about the lower speed. I have not idea how much force I need for the snow.

 

[George2615]

This is the design to use too. A floating blade with a chain. :thumbsup:

My first design was similar to the OP's drawing as a blade fixed to the QA plate with only the cutting edge that would trip.

It was easier to back drag with the fixed blade since I could use down pressure when pulling up to a garage door. Just the floating blade doesn't weigh enough to get through the hard packed snow for a better back drag. I have to figure a way to add something that will allow me to get down pressure on the blade using the curl function but still maintain the chain for a floating blade.

Here's my first design.

 

[LD1]

Thank you all for your quick answers! So SA cylinders and the cushion valve.



LD1 what about to go with bigger than 1.5, maybe 2" cylinders? I do not care about the lower speed. I have not idea how much force I need for the snow.

Why?

1.5" standard plow cylinders are readily available, cheap, and have worked on truck plows for decades.

Why reinvent the wheel

 

[polemidis]

I have no major arguments either way. The 2" cost $49.
:confused3:
Its going to the tractor, if that makes any difference